Elevated furnace support structure



Oct. 14, 1958 J. M. LEE 2,856,177

ELEVATED FURNACE SUPPORT STRUCTURE Filed July 25, 1955 2 Sheets-Sheet lJMAX LEE,

IN VEN TOR.

Oct. 14, 1958 J. M. LEE

ELEVATED FURNACE SUPPORT STRUCTURE 2 Sheets-Sheet 2 Filed July 25, 1955E ww R 0 )0 7 ET 7 N h W Q B J Mk w m mg U f M,

United States Patent F ELEVATED FURNACE SUPPORT STRUCTURE Jess Max Lee,North Hollywood, (Iaiif.

Application July 25, 1955, Serial No. 524,024

6 Claims. (Cl. 266--4) This invention relates to improved quenchingfurnace units for heat treating metals.

In heat treating metal parts for many uses, it is desirable to firstheat the part to a predetermined temperature, and then rapidly lower thetemperature of the part by submersion or quenching? within a body ofliquid. In my Patent No. 2,383,203 issued August2l, 1945 onHeat-Treating System, I have disclosed a furnace systern which isespecially adapted for this type of heating and quenching operation.This system includes a furnace which is supported in an elevatedlocation by a number of vertically extending support columns, andbeneath which there is provided a quenching pit filled with liquid. Anelevator is also provided for first moving a work load upwardly from aloading level into the furnace, then lowering the heated load into thequenching pit, and finally raising the load from the pit back to theinitial loading position for removal from the elevator. The furnace hasa door or doors at its underside adapted to pass the Work load and aportion of the elevator into and out of the furnace,

in a system of the above type, the elevated furnace is preferablyconnected to the vertical supporting columns by means of horizontallyextending metal frame members, which extend along opposite sides of thefurnace and are connected at their opposite ends to the verticalcolumns. In the past, difficulty has been encountered by reason of thelongitudinal expansion of some of these horizontal frame members whenthey become heated, usually by heat which escapes fromthe bottom of thefurnace past the doors. Specifically, such expansion of the horizontalframe members has had the effect of displacing or bending the verticalcolumns horizontally, with the result that the columns have been bowedsubstantially and the support of the furnace has thereforebeenmaterially weakened.

The general object of the present invention is to provide an improvedfurnace system of this type, in which the horizontal frame members arefree for longitudinal expansion without bending or bowing of thevertical columns to which they are connected. Specifically, I provideconnections between these elements which allow relative movement betweenthe horizontal and vertical members without impairing the supportconnection therebetween. For this purpose, I may employ a number ofsuspension members each of which is connected at an upper location toone of the vertical columns, and at a lower location to an end portionof one of the horizontal frame members. This suspension membereffectively supports the furnace and yet is free for lateral flexure ina manner allowing expansion of the horizontal member without deflectionof the vertical column. Connections of this type are desirably providedat each end of the two horizontal members. There may be a second pair ofhorizontal members, spaced above the first pair and out of the heatedzone, and which may be directly and rigidly nections.

2,856,177 Patented Oct. 14, 195

"ice

The above and other features and objects of the present invention willbe better understood from the following detailed description of thetypical embodiment illustrated in the accompanying drawings in which: I

Fig. l is a vertical section through a heat treating furnace andquenching system constructed in accordance with the invention;

Fig. 2 is a vertical section taken on line 22 of Fig. 1;

Fig. 3 is an enlarged fragmentary view taken on line 3-3 of Fig. 1, andshowing one of the furnace supporting expansion connections with whichthe invention isp'articularly concerned;

Fig. 4 is a section taken on line -4-4 of Fig. 3; and

Figs. 5 and 6 are sections taken on lines 5-5 an 6-6 respectively ofFig.1. 1

, Referring first to Figs. 1 and 2, the heat treatingsystern there shownincludes a furnace 10 supported by four vertically extending columns 11at an elevated location spaced above the level of the'floor 12. Beneaththe location of furnace 10, there is formed a quenching pit 13, whichextends downwardly well below the floor line 12, and which contains alarge body of water or quenching solution substantially filling the pit(say to the level L of Figs. 1 and 2). A hydraulically operated worksupporting elevator 14 is incorporated in the apparatus, and is capableof receiving a work load W at floor level (see Fig. 1), then elevatingthat work load into furnace 10 for heating, and then rapidly loweringthe work from the furnace into the body of quenching liquid within'p'it13, to rapidly reduce the temperature of the work. At its underside,furnace 10 has a pair of horizontally sliding doors 15 which are mountedfor movement toward and away from each other to allow passage of thework and an upper portion of the elevator into and out of the furnace.As will be apparent, the furnace, quenching .pit, and elevator are allpreferably of essentially rectangular horizontal section. As will bediscussed in greater detail at a later point, the invention isparticularly concerned with the manner in which the furnace 10 issupported from the upstanding columns 11.

The elevator 14 includes a hydraulic cylinder structure 16 stationarilymounted in the lower portion of quenching pit 13, and slidably receivinga vertically movable plunger or ram 17, which is adapted to behydraulically actuated upwardly from the Fig. 2 position to the Fig. 1position when pressurized liquid is fed to cylinder structure 16 througha suitably controlled system represented in part by feed line 18. At itsupper end, plunger 17 carries a horizontally extending frame structure19, which may be laterally engageable with a number of verticallyextending guides 20 for effectively guiding the elevator during itsvertical movement.

Frame structure 19 is never received within furnace 10, but carries asecond essentially horizontal platform or framework 120 which is spacedabove structure 19 and is received within the furnace during a heatingoperation. Platform 120 may include twoparallel horizontal channelshaped tracks 21 which are horizontally alined with the floor line 12 inthe Fig. 1 full line position of the elevator, and onto which the work Wmay be moved. Preferably, the work is carried by a suitable wheeledtruck or carriage, whose wheels move along and are. supported by tracks21. The two tracks 21 may be carried by several (typically three)transverse downwardly facing channel members 22, which are supportedfrom frame structure 19 by individual vertically extending telescopingsupport posts 23 of externally cylindrical configuration. The

inner abutting edges of the two furnace doors 15 are provided withopposed semicircular recesses 24 of a. size to attached to the verticalcolumns without expansion conreceive posts 23 when doors 15 are closedwith platform and the work positioned within the furnace 10, so that thedoors embrace posts 23 and along with those posts a j '3' act tosubstantially completely close off the the furnace.

The rectangular or box like furnace is defined by two parallel somewhatelongated vertically extending side ,walls 25, two parallel end walls26, and an upper horizontal wall 27. All of these walls are formed ofsuitable refractory brick or other heat insulative material, with theside and end walls typically being formed of several :layers ofdifferent types of refractory material as shown. The interior of thefurnace may be heated in any suitable manner, as by suitable heatersrepresented at 28. The heated air may be circulated within the furnaceby means of a blower 29 (or byi-nternal fans), with the circulating .airbeing directed along a desired path by means of suitable baffies andducts 30. The refractory side and end walls 25 and 26 are carried bymetal castings 31 of the illustrated sectional configuration, and whichextend across the undersides of the side and end Walls, and may projectlaterally outwardly beyond those "walls.

About the outside of the side and end walls 25 and 26,

underside of there is provided an outer metal housing 32, formed ofrelatively thin vertically extending sheet metal. At its lower end, thesheet .metal 32 forming the outer housing of the furnace is confinedwithin a rectangular framework formed by two outwardly facing channels33 extending along opposite sides of the lower portion of the furnace,.and two similar channels 34 extending along the opposite ends of thefurnace at its lower edge. These channels 33 and'34 may be attached tothe outwardly projecting portions of castings 31, as'by means of aseries of stainless :steel bolts 35 extending through andinterconnecting the castings and the lower webs of the channels. At thefour corners of the furnace. the channels 33 and 34 are rigidly attachedtogether, typically by means of an angle iron 135 (see Fig. 6) bolted toboth of the channels being interconnected.

The end channels 34 project laterally beyond the rest of the furnace,and serve as tracks at opposite ends of 'the furnace. along which anumber of rollers 36 supporting doors are horizontally movable. Theserollers 36 may be .rotatably carried by frame members- 37 which projectupwardly from opposite ends of doors 15, so that the doors areeffectively supported for horizontal movement toward and away from eachother to allow the work to pass into and out of the furnace. Doors 15preferably contain a refractory or heat insulative material forpreventing heat loss through the doors. The relatively sliding surfacesof the doors and furnace are of course preferably so formed or sealed asto minimize heat loss rigidly welded or otherwise attached in fixedrelation to -the upper ends of the four supporting columns 11. Verti-"cally between the upper and lower channels, there may be provided aseries of vertically extending rigid frame 'members 40 of T-shapedhorizontal section, which .may

"be welded at their upper ends to channels 38 and 39, and at their lowerends to channels 34 and a pair of channels or beams41,-and which act toassist in retaining and bracing :the side and end walls of the furnace.

The two channels 41 are provided for attachingthe "lower portion of thefurnace to the four supporting columns 11 at the opposite ends of thefurnace. These channels 41 extend horizontally along the opposite sidesof the furnace, above the lower side channels 33, and arerigidlyattached to channels 33, as by a series of spaced connecting bolts 42whichconnect together the abutting webs of channels 33 and 41, As in the.case of upper side channels 38, channels 41 project beyond the ends ofthe furnace for attachment to columns 11.

Each of the four columns 11 projects vertically upwardly from floor 12,and is attached in fixed relation to the floor at the lower end of thecolumn by means of a suitable stationary base member 43, which may bebolted to the floor. The columns 11 are formed of structural steel, andare H-shaped in horizontal section (see Fig. 4). The webs 44 of columns11 lie in planes which extend longitudinally oif the furnace, that is,parallel to side walls 25, while the flanges 45 of columns 11 projecttransversely with respect to the furnace. The two flanges 45 of eachcolumn 11 which project laterally away from the furnace are cut away at46 to form a recess within which one end of one of the longitudinalfurnace support channels 41 is received. The vertically extending webportion 47 of that channel 41 is then received directly adjacent thevertically extending web portion 44 of column 11 at the locations .atwhich flanges 45 are cut away.

The end of channel 41 is supported from column 11 in this position (seeFigs. 3 and 4) by means of a vertically extending preferably metalsuspension or tension member 48, which extends downwardly along one ofthe flanges 45 to a position opposite the end of channel 41. The upperend of suspension member 48 is rigidly attached to flange 45 at alocation spaced above channel 41, preferably by means of a number ofattaching bolts 49. At its lower end, suspension member 48 is attachedby bolts 50 to a member 51 which is rigidly attached to channel 41.Member 51 may be a rigid piece of metal, plate or angle say aboutone-half inch in thickness, extending across the end of channel 41, andrigidly welded or bolted to channel 41 along the engaged portions of theweb 47 and flanges of channel 41. The end of channel 41 may be retainedagainst web 44 of column 11 by means of several, typically four, bolts52 extending through openings 53 in column web 44, and throughhorizontally elongated slots 54 in web 47 of channel 41. Bolts 52 haveenlarged heads at the outer side of channel 41, which heads are largerthan and can not pass through slots 54, so that the bolts retain channel41 against web 44 of the column, while at the same time allowinglongitudinal movement of channel 41 relative to the column. Bolts 52 aresufliciently loose to allow such longitudinal movement of channel41relative to the'column. As will be apparent, a connection such as thatshown in Figs. 3 and 4 is provided between each end of each of thehorizontal channels 41 and an associated one of the four verticalcolumns 11.

In using the illustrated furnace structure, elevator '14 is first sopositioned that its work supporting platform 120 is alined with floor12, following which a work supporting truck is rolled onto platform 120along tracks 21. Doors 15 of the furnace may then be opened by suitableoperating mechanism (not shown), and elevator 14 is then hydraulicallyactuated to raise the work W and platform 120 into the furnace. Doors 15may then be closed beneath'platform 120, to close off the underside ofthe furmace and allow heating of the work within the furnace. After thework has been raised to a proper temperature, doors 15 are opened, andelevator 14 is allowed to fall rapidly to immerse work W within thequenching liquid in pit 13. After the quenching operation has beencompleted, the elevator is again raised to the Fig. 1 position, so thatthe work may be rolled ofii of platform 120, and a next successive loadmay be moved onto the platform.

During operation of a furnace of this type, a considerable amount ofheated air may flow past doors 15 to the outside of the furnace, andusually results in the heatto expand longitudinally, and if the ends ofthese channels 41 are rigidly attached to columns 11, the expansion ofchannels 41 will result in the bowing of columns 11 in directions awayfrom the end of the furnace. The unique expansion connections shown inFigs. 3 and 4 prevent such bowing of columns 11 even though channels 41may expand. Specifically, when channels 41 are heated and begin toelongate, the suspension members 48 are able to flex, as between theirfull line and broken line positions of Fig. 3, so that the end of thechannel 41 moves longitudinally relative to the supporting columns 11without damage to either part. Also, such lateral flexure of thesuspension member 48, which is in essentially a state of simple tension,does not in any way damage the suspension member. When the temperatureof channels 41 subsequently reduces, members 48 merely flex back totheir original vertical positions, without bowing of any of the columns11 during either expansion or contraction. In order to allow for thedesired flexure of member dis without damage to that member or any ofthe other parts, the portion of member 48 which is capable of flexureduring expansion of channel 41 may typically be of a length of about 24inches. The upper channels 38 at the top of the furnace may be rigidlyattached directly to the upper ends of columns 11, rather than beingconnected by means of an expansion connnection such as that shown inFigs. 3 and 4, since relatively little of the heated air reaches thechannels 38, and there is consequently no substantial heat inducedexpansion of these channels.

I claim:

1. Heat treating apparatus comprising an elevated furnace having anopening at its underside, a pit beneath said furnace containing aquenching liquid, an elevator for supporting work pieces and adapted tomove said work pieces vertically between an elevated position in saidfurnace to be heated thereby and a lowered position of immersion in saidquenching liquid, means for substantially closing said underside of thefurnace with said work pieces supported therein by the elevator, andmeans for supporting said furnace including a pair of vertical supportcolumns, a substantially horizontal member supporting said furnace andconnected near opposite ends respectively of the member to said twocolumns, and an expansion connection between said member and one of saidcolumns supporting the member from the column but allowing longitudinalmovement of the member relative to the column when the member expandsupon heating, said expansion connection including a vertically extendingsuspension element attached at an upper location to said column andhanging downwardly substantially directly vertically from said upperlocation and alongside said column to a lower location, means attachingsaid suspension element at said lower location to said member to suspendthe member from the column, said suspension element having a thicknessdimension longi tudinally of said member which is small as compared withthe vertical length of the element, said suspension element beingadapted to flex longitudinally of said member to allow said longitudinalmovement of the member relative to said column, said one column being ofessentially H-shaped cross sectional configuration having a cross weband flanges projecting therefrom, said horizontal member being a channelmember having a web portion adjacent and parallel to said web of thecolumn, said flanges having cutaway areas at the location of andreceiving said channel member, and said suspension element beingconnected to one of said flanges of the column at a location above saidcutaway area thereof, and being connected to said horizontal member atsaid cutaway area.

2. Heat treating apparatus as recited in claim 1, including a boltcarried by one of said webs and projecting through a slot in the otherweb to guide the member for only said longitudinal movement relative tothe column.

3. Heat treating apparatus as recited in claim 2, including a connectordisposed across and welded to an d end of said channel at the locationof said cutaway area of said one flange and connected at that locationto said suspension element.

4. Heat treating apparatus comprising an elevated furnace having anopening at its underside, a pit beneath said furnace containing aquenching liquid, an elevator for supporting work pieces and adapted tomove said work pieces vertically between an elevated position in saidfurnace to be heated thereby and a lowered position of immersion in saidquenching liquid, means for substantially closing said underside of thefurnace with said work pieces supported therein by the elevator, andmeans for supporting said furnace including two beams carrying thefurnace and extending generally horizontally and generally parallelalong opposite sides of the furnace at the lower portion thereof andprojecting beyond opposite ends of the furnace, two pairs of verticallyextending columns supporting opposite ends of said two beamsrespectively, four expansion connections supporting the ends of said twobeams from said columns but allowing longitudinal movement of themembers relative to the columns at said connections when the beamsexpand upon heating, each of said connections including a verticallyextending metal suspension element attached at an upper location to theassociated column and hanging downwardly substantially directlyvertically from said upper location and alongside said column to a lowerlocation means attaching said suspension element to an associated one ofthe beams at said lower location to suspend the beam from the column,said suspension element having a thickness dimension longitudinally ofthe beam which is small as compared with the vertical length of theelement, and said suspension element being adapted to flexlongitudinally of the associated beam to allow said longitudinalmovement of the beam relative to the column, a second pair of beamsextending along and supporting said opposite sides of the furnace abovesaid first beams and having their ends rigidly attached to said columns,said columns being H-shaped in section, and said two pairs of beamsbeing channels having web portions adjacent the cross webs of saidH-shaped columns, said flanges having cutaway areas within which saidbeams are received, four plates disposed across and secured to the endsof said channels, at approximately said cutaway areas of the columnflanges, each of said suspension elements being bolted at an upper endof a flange of the associated column and at a lower end to one of saidplates and being adapted to flex longitudinally of said beams, and aplurality of bolts carried by one of said webs at each of saidconnections and passing through slots in the: other web to guide thebeam for only longitudinal movement relative to the columns.

5. Heat treating apparatus comprising an elevated furnace having anopening at its underside, a pit beneath said furnace containing aquenching liquid, an elevator for supporting work pieces and adapted tomove'said work picees vertically between an elevated position in saidfurnace to be heated thereby and a lowered position of immersion in saidquenching liquid, means for substantially closing said underside of thefurnace with said work pieces supported therein by the elevator, andmeans for supporting said furnace including a pair of vertical supportcolumns, a substantially horizontal member supporting said furnace andconnected near opposite ends respectively of the member to said twocolumns, and an expansion connection between said member and one of saidcolumns supporting the member from the column but allowing longitudinalmovement of the member relative to the column when the member expandsupon heating, said expansion connection including a vertically extendingsuspension element attached at an upper location to said column andhanging downwardly substantially directly vertically from said upperlocation and alongside said column to a lower location, means attachingsaid suspension element at said lower location to said member to suspendthe member from the column, References Cited in the file of this patentsaid suspension element having a thickness dimension UNITED STATESPATENTS longitudinally of said member which is small as compared 370Bataan Tan 1944 with the vertical length of the element, said suspension5 Lee 1945 element being adapted to flex longitudinally of said mem- LeeJam 1949 her to allow said longitudinalimovement of the member 2,641,575Otto June 9, 9 relative to said column.

6. Heat treating apparatus as recited in claim 5, :in- OTHER REFERENCESeluding a slot and headed pin connection retaining .said 10 W. Trinks;Industrial Furnaces, vol. 1, page327 4Yh'ed. member against lateralseparation from said column. 1950.

